Sprinkler systems having a plurality of pop-up type sprinkler heads are well known and involve sophisticated individual watering heads for large scale irrigation of parks, golf courses and the like. Such systems involve a lateral line fitted with a plurality of heads for that one line. The various lateral lines are fed from larger water supply pipes. Electrical control is commonly provided from a master control box electrically connected to and remotely located from each of the individual heads.
On each lateral line supplied by a larger water supply pipe, the individual heads are designed for an optimum water pressure. Spacing along the lateral line during an original installation is determined by parameters based upon a given number of individual heads operating at a presumed water pressure that is idealized for the individual heads. The area of coverage by each head is also a function of the individual head's supply pressure. Skill is required to design a lateral layout to suit the particular watering needs of the contours and areas for each lateral line with its plurality of individual heads.
At the point of connection of each head on a single lateral line, the amount of supply pressure varies as one moves from the supply source to the last head on the line. More pressure is available at the head of the line at the point closest to the supply source than is available at the last terminating head on that lateral. Each individual head during installation of the system may be supplied with an individual pressure adjustment usually located at the area where the head is connected to the water supply line. The adjustment mechanism is thus normally located at an underground location after the system is installed. One typical prior art valve of the type that requires digging is shown in U.S. Pat. No. 4,226,259. While the valve of the identified patent is asserted to apply to pressure regulation it is not applicable to individual head pressure adjustment with the features provided by this invention.
If the overall system design is not perfect or if the optimum pressure, at some later time, is not achieved the coverage pattern for the heads on that lateral may turn out to be defective. One solution is to dig underground and attempt to read and individually vary the pressure adjustments so that some heads may have more pressure than others.
The master electrical control is located remotely from the heads and this distance increases the complexity of the pressure adjustment task. If all of the heads are provided with individual manual on/off control, pressure adjustment is somewhat simplified. A manual on/off control for an individual head is, of course, well known.
Pop-up heads when not in use are often recessed in a housing and the spray nozzles are covered by an upper cover. These heads rely upon water pressure inside the sprinkler to pop-up the head and also to rotate the head while it is spraying. Water exiting from the spray nozzles also drives the head's nozzle in rotation as it sprays an area. If coverage after installation is not adequate the spray pressure must be read and if possible, adjusted relative to the spray pressure of other heads on the given lateral.
One technique used to read the spray, or outside water pressure, is to employ a pitot tube which is affixed to a standard pressure gauge. A technician, when the system is operating, inserts the pitot tube at the nozzle location into the exiting spray. The tube is manually moved around in the exiting spray in an attempt to locate the highest spray pressure. The pitot tube affects the spray, disrupts the spray nozzles movement, and at best is an approximate reading. The technician gets soaked and is not at all confident of the exactness of his readings.
In some dual nozzle pop-up heads, one nozzle does the spraying while a secondary nozzle drives the head for rotation. In this dual-nozzle type the drive is not interrupted by the pitot tube, but the spray reading is still affected by the presence of the pitot tube in the spray. One still gets soaked and does not have confidence in the pressure readings.
Since the pressure adjustment for individual heads in the prior art is located underground the operating personnel must dig up the heads to achieve individual adjustments. Moreover, the adjustments must be done while moving the pitot tube around in the spray and cannot be done by a single technician. In general the prior art pressure adjustments present a difficult and inexact task which often involves several people.
What has not, prior to this invention, been readily available is a remotely controlled pop-up head that can easily and simply have each head's internal pressure read directly and adjusted by one person who remains dry during the task and has confidence in the correctness of the pressure readings.